1. Field
This invention relates to a cell apparatus which transmits AC (Alternating Current) power by wireless transmission to make transmission of AC power possible without contacts.
2. Discussion of the Background
A conventional secondary cell supplies DC (Direct Current) power to an electronic equipment of the portable type or the like and normally has a cylindrical shape or a square pole shape. The conventional secondary cell uses two positive and negative contacts, or terminals, to carry out charging and discharging therethrough.
FIG. 13 is a schematic diagram of a conventional secondary cell in a charging or discharging state. Referring to FIG. 13, the secondary cell 1 shown has a cylindrical shape and has a positive contact 2 on one end side of the cylinder in the direction of a center line thereof and a negative contact 3 at the other end side of the cylinder.
Usually, the secondary cell 1 is accommodated in a cell accommodating recess 4A provided on a housing 4 of a charger or an electronic equipment and carries out charging or discharging. In the cell accommodating recess 4A, for example, a leaf spring 5 made of a conductive metal material is provided such that the positive contact 2 of the secondary cell 1 is electrically coupled thereto, and, for example, a coil spring 6 made of a conductive metal material is provided such that the negative contact 3 of the secondary cell 1 is electrically connected thereto.
Where the housing 4 is provided on a charger, charging current Ic from a charging circuit 7 flows to the secondary cell 1 as seen in FIG. 14A to charge the secondary cell 1.
On the other hand, where the housing 4 is provided on an electronic equipment, discharging circuit Id from the secondary cell 1 flows to a load circuit 8 of the electronic equipment as in FIG. 14B and power is consumed by the load circuit 8.
Where such a conventional secondary cell 1 as described above is used, it exhibits such characteristics and problems as described below.
(1) It is necessary to connect the secondary cell and a circuit board in the inside of a charger or an electronic equipment by wire connection using a cable.
(2) In order to replace the cell in an electronic equipment, it is necessary to expose a cell accommodation section, and it is difficult to use an enclosed or waterproof structure for the electronic equipment.
(3) The contacts or terminals of the secondary cell must always be kept in a dirt-free state.
(4) Where the secondary cell is accommodated in an electronic equipment, it is necessary to provide a cell lid for the cell accommodating section to prevent coming off of the cell. It is to be noted that, where the secondary cell is configured integrally with a lid, such a cell lid as mentioned above is not required. However, where the secondary cell is of the type described, there is a drawback that the charger is configured for exclusive use for the cell.
(5) In a state wherein the secondary cell is accommodated in the cell accommodating section, since spring pressure is applied to the secondary cell in order to establish assured contact, it is not easy to take out the secondary cell.
(6) It is necessary to mechanically absorb the tolerance in size of the secondary cell.
(7) Since resiliency is required for a terminal on the cell accommodating section of a charger or an electronic equipment for accommodating a secondary cell, a useless expansion/contraction space is required for the charger or the electronic equipment.
(8) Since it is necessary for the terminals of the secondary cell to be exposed, it is difficult to prevent leakage of the cell liquid.
(9) Since the common secondary cell is accommodated in the cell accommodating section of an electronic equipment and used, one cell can drive only one electronic equipment at a time.
In order to solve the problems between a charger and a secondary cell described above, a contactless re-chargeable cell and a charger therefore wherein charging of a secondary cell is carried out by electromagnetic induction have been proposed in Japanese Patent Laid-Open No. 2005-117748 (hereinafter referred to as Patent Document 1).
According to the disclosure by Patent Document 1, the charger includes a primary coil for electromagnetic induction, and the contactless re-chargeable cell includes a secondary cell which excites induced current through an electromagnetic induction relationship to the primary coil. In the contactless re-chargeable cell, the current induced in the secondary coil is rectified into DC and a built-in secondary cell is charged with the DC.
When the contactless re-chargeable cell is incorporated in and used together with electronic equipment, it can be used quite similarly to a common dry cell or a common secondary cell. In particular, the contactless re-chargeable cell includes positive and negative contacts and can be used quite similarly as with a common dry cell or secondary cell by connecting the contacts to terminals of a cell accommodating section of an electronic equipment which are individually formed from a leaf spring and a coil spring.
The contactless re-chargeable cell of Patent Document 1 described above are improved in regard to the problems of the items (1), (5), (6) and (7) regarding the relationship between a charger and a secondary cell. However, the contactless re-chargeable cell of Patent
Document 1 exhibits no improvement in regard to the other problems described above because it includes positive and negative metal contacts such that, when it is used, the metal contacts are connected to terminals of the cell accommodating section of an electronic equipment which are individually formed from a leaf spring and a coil spring.
Therefore, it is desirable to provide a secondary cell apparatus which can solve all of the problems of the items (1) to (9) described hereinabove by carrying out not only charging but also discharging in a contactless fashion.